Flow limiter



April 14, 1959 L. E. ALDWIN ErAL 2,381,794

FLOW LIMITER INVENToRs [if E'. BALDw/N By 17A/@WQ BoKELMA/v 2,881,794FLoW LIMITER Lee E. Baldwin and Marinus C. Bokelman, Los Angeles,

Calif., assignors to Conair, Inc., Glendale, Calif., a corporation ofCalifornia Application March 29, 1957, Serial No. 649,546

Claims. (Cl. 137-501) This invention relates to a flow limiter valveconstruction and more particularly to such a construction for use inhydraulic systems to control the volumetric rate or ilow of fluid topumps or fluid operated servo units andv the like in the systems. y

It is a general object of the present invention to provide a novel andimproved ow limiter or valve construction adapted to be engaged in afluid handling pipeline and which is responsive to hydraulic pressurewithin the line for automatically regulating the volumetric rate or flowof fluid therethrough. a

Another object of the present invention is to provide a construction ofthe general character referred to which is not materially affected byvariations in the heat and viscosity of .the fluid being handled andwhich is responsive to slight variations in pressure and surging of thefluid being handled.

A feature ofthe present invention is to provide a ow limiter of thecharacter referred to having a tubular body, a tubular uid conductingsleeve within the body with longitudinally spaced lateral openingstherein and a spring loaded-pressure responsive spool or plunger withinthe sleeve and controlling the flow of fluid therethrough. The plungeris 'adapted to cooperate with the upstream openings in the sleeve tocontrol the flow of fluid into the sleeve, while the downstream openingsin the sleeve serve to conduct the fluid from within the sleeve andestablish a pressure drop in the construction for operation of theplunger.

Another feature of our invention is to provide a ilow limiter whereinthe upstream or ow controlling openings in the sleeve are of novelconfiguration to elect a wide variation in flow upon limitedlongitudinal shifting of the spool relative thereto.

A further object of the present invention is to provide a constructionof the character referred to which is neat and compact, which is easyand economical of manufacture and which isV both highly effective anddependable in operation,

The various objects and features of our invention will be fullyunderstood from the following detailed description of a typicalpreferred form and application of our invention, throughout whichdescription reference is made to the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional view showing our Fig. 6 is atransverse sectional view taken as indicated by line 6-6 on Fig. 1.

2,881,794 Patented Apr. 14, 1959 ICC i The flow limiter constructionprovided by the present invention and illustrated throughout thedrawings Ais adapted to be engaged in a pipeline P and is shown asincluding an elongate tubular body A, an elongate tubular uid handlingsleeve B engaged in the -body and defining longitudinally spacedupstream and downstream annular chambers X and Y, an elongate liluidpressure responsive valving member or plunger C slidably engaged in thesleeve and controlling the flow of fluid therethrough and from onechamber to the other, spring means D normally yieldingly urging theplunger Cto-an unactuated position, and buffer means E controlling theaction of the plunger C and the spring means D.

,The body A is an elongate member having front and rear endportions 10and 11, a central longitudinally disposed inlet passage 12 of limitedlongitudinal extent entering the body from its forward end andterminating at a flat 'bottom 13, a central longitudinally disposed bore14 vof considerable longitudinal extent entering the body A from itsrear end and terminating at a flat bottom 15 inthe forward portion 10 ofthe body, and spaced from the bottom of the inlet passage 12 and aplurality of circumferentially spaced ports 16 extending between andestablishing open communication with the passage 12 and the bore .14.The bore 14 is substantially larger in diameter than the inlet passage12, and the ports 16 diverge rearwardly from the bottom of the passage12, and communicate with the bore 14 about the outer periphery of thebottom 15 thereof, as clearly illustrated in Figs. 1 and 2 of thedrawings.

The forward end portion of the inlet passage 12 is internally threadedas at 17 to threadedly receive the end of a pipe 18 of the pipeline P,while the rear end portion of the bore 14 is internally threaded as at19 to threadedly receive a suitable plug 20. The plug 20 engaged in thebore 14 is an elongate element having front and rear portions 21 and 22and a vcentral longitudinal outlet passage 23 extending therethrough toestablish open communication with the interior of the body. The rearportion of the outlet passage 23 is threaded as at 24 to threadedlyreceive a pipe 25 of the pipeline P. t

. The rear portion 22 of the plug 20 is externally threaded as 'at 26lto cooperatively engage with the threads 19 in the bore 14, while theforward portion 20 of the plug slidably enters the bore 14 and carries asuitv able sealing lmeans 27 to seal between the plug and the bore. Inthe case illustrated, the sealing means 27 is shown as including 'anannular groove 28 about the exterior of the plug and suitable packingrings 29 engaged in the groove and sealing with the bore.

The plug 20 has a flat radially disposed inner or front face 30, whichface is provided with a plurality of radially disposed notches 31adapted to conduct fluid from the rear and outer peripheral portion ofthe bore defining the downstream chamber Y, to the outlet passage 23 aswill hereinafter be described.

Y In the particular case illustrated, a suitable lock nut 32 is providedon the outer or rear end portion of the plug 20 to engage the body A andto maintain the plug in fixed position therein.

The fluid handling sleeve B is an elongate tubular member engaged in thebody A to extend between the bottom 15 of the bore 14 rand the innerface 30 of the plug 20. The sleeve B is substantially smaller indiameter than the bore 14 and is arranged coaxially therewith toestablish an annular space between the exterior of the sleeve and theWall of the bore. A radially outwardly projecting flange-like partition40 is provided on the sleeve, intermediate its ends, to slidably engagein the bore of the body and to divide the said space into the bers X andY, respectively.

The' partitionv 40 is shown provided with an annular groove' 4-3about-its outer periphery and in which'suitable` sealing rings 44 areengaged' to seal with the bore and prevent passage of iluid from onechamber to the other.

The sleeve' B is further provided with a` central longitudiiial cylinderbore 45 extending from one eiid there"-A of tothe other, one or morecircumferentially spaceidl'at-V eral metering' ports 46 in the forwardportion of theslee've and establishing open communication'l between theVupstre'ar'n-k or inlet chamber X and the cylinder'bor'e- 45t;

and one or lmore circumferentially spaced substantially radiallydisposed orifices 47 spacedV longitudinally rearw'a'r'dly of the ports'-46 and establishing opencommunica@ tion between the cylinder bore andtheY downstreanl` `or4 outlet chamber Y.

t The freut and reary ends ofthe sleeve B arev closed by' suitable frontand rear heads 4s eind 49, respeetlveiy. Each head is shown as includinga plug-like' body slidably engaged in the cylinder bore and al radiallyt'mtvvardiyV projecting flange corresponding in outside diameter withthe sleeve B and adapted to overlie its related end lof the sleeve'andto be held in clamped relationship between the said end of the sleeveand the bottoni 15 of the bore 14,' or the end face 30 of the plug 20.

Iii the case illustrated, a suitable sealing means- 50 is provided aboutthe body of each head to prevent leali-Y age or the passage of Huidthereby.

With the bov'e relationship of parts, it will be appar'eut that iiuid inthe pipe 18 engaged in the forward end lof the body A and communicatingwith the inlet passage 12., hows freely into the upstream or inlet cham=berA X through the duet 16, whereupon it ows into the cylinder bore 45iii the sleeve B through the metering, ports 4 6. The huid then howsoutwardly from the yl= iiidei bore 45 through the OriCes 47 into thelltlet chamber-Y where it then free to flow through the notches si inthe end face 30 of the plug 20 into the ont: l'et passage 23 and intothe pipe 25 engaged in the plug.

In practice; the orifices 47 are of limited cross-section and serfv' toestablish a pressure drop between the cylinder bore and the downstreamor outlet chamber The vplunger is an elongate longitudinally disposedspoo'lflike valving member having a rearwardly opening cup-shaped base60 having sliding sealing engagement in the rear end portion ofthecylinder bore 45 in the lsfleevte B aid spaced from and opposing the'rear head 4`9, anv

c lihgt'e shank k'6 1 reduced diameter proecting forwerdlv from thebese, pa-st vthe entrees and the metering ports 47 and 46, and 'snelongate pist-en heed 62 at tite fervent ell-dier the shank andestablishing sliding-sealing' engagement with the cylinder bore 45 andadapted to op` pose the ferward head '48 in the sleeve and to nrnallyocenriforwar'd of themeteng ports 216 in the sleeve.Y

iheplunger further providedwi'th a 'cei'itralu long`itudinal1y d `sposed How passage 65 'entering it vfrom the terminal end thereof andterminating at a, iatei'ts'eIIdS, 'and 'a lateral prt 1'6'6 in the pointintermed 61a e-stablisliing Yopen communication between th passage'65"at1d the cylinder bore 45, between the head andthe 'base oftheplunger.

the above relationship of parts, it will be apparent thathuid`introduced into the lanniilus abcut the shank '61 'of the plunger C,vthrough the metering ports 46, is conducted to the forward end'of thecylinder bore 4'5, 'te eet on tire piston heed 62 end normaux/urges theplung'er rearwardly 'in the cylinder bore. The piston neadjoz te adaptedyto overltfe 'portions 'of the int-.tering ports 46 when the pistonlie'ad 62 is shifted rerwarfd, to. restrict and control the how of Huidtherethrough and, 'in 'a inanne'r that "will 'h'erefnaffer be described.

The "spring nte-ens D is adapted to 'normally yieldlngl'v urgethejpliing'erfC forwardly inthe cyclinder bore 45 'and to "counteractand balance the force of the iluid acting on the 1piston head 62, and isshown as including la compres- 4 sion spring 70 engaged between theplunger C and the head 49 at the" rear endof thesleeveB". Intheparticular case illustrated, the forward portion of the spring 70 isengaged in and carried by the rearwardly opening cupshaped base 60 ofthe plunger C while the rear portion is engaged or seated in a bore 71provided in the forward end of the body of the head 49;

The buffer means E is Iadapted to limit or control the rate at which theplunger C can move in the sleeve B, as a resultL of'fluid actioriwithinythe structure oras a result of the action of the spring 70 of the meansD: In the case illustrated, the means E is shownas including a counterbore 73 continuing, from thebottom of they bore 71 in the head" 49' atthe rear end ofthe sleeve B and an orice 74 continuing rearwardly fromthe eounterbore and establishing open communication between the outletpassage 23 in the plug 20 and the space occurring between the base 60 ofthe plunger and the head 49.

With the 4structure set forth above, it will be apparent that when the'fluid pressure forward or upstream of the orifices 47` in the sleeve Band dering on the piston head 62, overcomes" the resistance afforded bythe spring 70, the piston head moves rearwardly to overlie the meteringports 46 in the sleeve, thereby restricting the flow of uid therethrdgh.The piston continues to move rearwardly until suticient' ow is shut offthrough the metering ports sothat pressure of the huid acting on thepiston head is 'balanced with the force exerted by the spring 70 of themeans D.

It will be further apparent that as the upstream pressure increases,decreases, or surges, and the plunger C is shifted iii the cylinder bore45 of the sleeve B, the rate at which the plunger can movers limited andthe action of the device is smoothed out by the buffer' means E, thatis, bythe restricted flow of uid through the oriee 74l in the head 49.

Iii 'the preferred form of the invention, the metering puits 46 in thesleeve B and with which the piston head 62 of the plunger C cooperatesto. control the rate of now through the device are of novelconfiguration so that a wide variation of flow can be obtained with aminimum amount of movement b`y the plunger, and with the result that thedevice is highly Asensitive and rapid in operation.

The metering ports 46 are shown as being of semicurvilinear triangularconfiguration, the base 76 being straight and extending transverse thelongitudinal axis of the "si'eeve and the sides '77 being convex andconverging rearwardly relative to the longitudinal 'axis of the sleeveas 'clearly illustrated in Figs. 3 'and 4 of the drawings. With thisconigurat'ion, it will be apparent that prior vto rearward shifting 'oractuation of the 'piston head 62 where it 'overlies a portion of theports, the ports afford maximum and free ow of fluid into 'th'e'cylinder bore 45. It will be further apparent that when 'the pressureacting upon 'the piston h'ead overcomes the resistance afforded 'by the's'p'rin'g 70 'and shifts the head rearwardly to overlie the v'p'c1"`ts', the rate of ow through the ports is progressively and smoothlyrestricted.

The curvature of the sides 77 of the ports 46 is governed or controlledbythe particular characteristics of the spring 70 of the means D, thatis, its strength and variations -in resistance as it is compressed.

IIn practice, where the 'structure provided 'by the present invention isdesigned to operate in la particular pressure range, a spring 7 0 of theproper strength must be provided Vand the configuration of the meteringports '46 must be hanged :for variedaec'ordingly.

With the 'structure that 'we provide, it will be apparent that by thearrangement and relative positioning 'of Athe meter'ingpbrts "46 andorifices 47, which establish the required .pressure drop in the devicefor operation, the rate o'fhw'ttfrngh'tlre or'ees'rsfnaintinedsbstantially Vcottstant with theresult that the change inviscosity of the fluid lgenerated by the friction of the fluid passingtherethrough, remains substantially constant.

Having described only a typi-cal preferred form and application of ourinvention, we do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to ourselves anyvariations or modifications that many lappear to those skilled in theart and fall within the scope of the following claims.

Having described our invention, we claim:

l. A flow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage in the front end of thebody and an outlet passage in the rear end of the body, a longitudinallydisposed cylinder bore in the body, a metering port establishing opencommunication between the inlet passage and the forward portion of thebore, an orifice establishing open communication between the rearportion of the bore and the outlet passage and adapted to establish apressure drop between the inflowing fluid and the outflowing fluid, anelongate plunger in the bore and having a piston head at one end tonormally occur forward of the metering port and establishing slidingsealing engagement in the bore, a base at the other end of the plungerto occur rearward of the orifice and establishing sliding sealingengagement in the bore, means conducting fluid upstream of the orificeinto the bore forward of the piston to shift the piston rearwardly tooverlie the metering port and to control the flow of fluid therethrough,means conducting iluid downstream of the orifice into the bore rearwardof the base, and spring means in the bore to act on the base of theplunger and normally yieldingly urging the plunger and the pistonforwardly in the bore.

2. A flow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage in the front end of thebody and an 'outlet passage in the rear end of the body, alongitudinally disposed cylinder bore in the body, a plurality ofcircumferentially spaced metering ports establishing open communicationbetween the inlet passage and the forward portion of the bore, aplurality of circumferentially spaced orifices establishing opencommunication between the rear portion of the bore and the outletpassage and adapted to establish a pressure drop between the inowing andoutllowing fluid, an elongate plunger in the bore and having a pistonhead at one end to normally occur forward of the metering ports andestablishing sliding sealing engagement in the bore, a base at the otherend of the plunger to occur rearward of the orifices and establishingsliding sealing engagement in the bore, means conducting fluid upstreamof the orifices into the bore forward of the piston to shift the pistonrearwardly to overlie the metering port and control the flow of fluidtherethrough, means conducting iluid downstream of the orifices into thebore rearward of the base, and spring means in the bore to act on thebase of the plunger and normally yieldingly urging the plunger and thepiston forward in the bore.

3. A flow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage in the front end of thebody and an outlet passage in the rear end of the body, a longitudinallydisposed cylinder bore in the body, a metering port establishing opencommunication between the inlet passage and the forward portion of thebore, an orifice establishing open communication between the rearportion of the bore and the outlet passage and adapted to establish apressure drop between the inllowing and outflowing fluid, an elongateplunger in the bore and having a piston head at one end to normallyoccur forward of the metering port and establishing sliding sealingengagement in the bore, a base at the other end of the plunger to occurrearward of the orifice and establishing sliding sealing 6 with'the flowpassage to conduct fluid upstream of the' orifice into the bore forwardof the piston to shift the piston rearwardly to overlie the meteringport and control the flow of fluid therethrough, buffer means conductinguid downstream of the orifice into and out of the bore rearward of thebase to control the rate of movement of the plunger, and spring means inIthe bore to act on the base of the plunger and normally yieldinglyurging the plunger and the piston forward in the bore.

4. A flow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage in the front end of thebody and anoutlet passage in the rear end of the body, a longitudinallydisposed cylinder bore in the body, a semi-curvilinear triangularmetering port having a base extending transverse the longitudinal axisof the body and rearwardly convergent convex sides, establishing opencommunica- Ition between the inlet passage and the forward portion ofthe bore, an orifice establishing open communication between the rearportion of the bore and the outlet passage and adapted to establish apressure drop between the inilowing and outllowing fluid, an elongateplunger in the bore and having a piston head at one end to normallyoccur forward of the metering port and `establishing sliding sealingengagement in the bore, a'base at the other end of the plunger to occurrearward of the orifice and establishing sliding sealing engagement inthe bore, means conducting fluid upstream of the orifice into the boreforward of the piston to shift the piston rearwardly to overlie themetering port and control the flow of fluid therethrough, meansconducting fluid downstream of the orifice into the bore rearward of thebase, and spring means in the bore to act on the base of the plunger andnormally yieldingly urging the plunger and the pistonA forward in thebore.

5. A flow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage in the front end of thebody and an outlet lpassage in the rear end of the body, alongitudinally disposed cylinder bore in the body, a plurality ofcircumferentially spaced semi-curvilinear triangular metering portshaving rearwardly convergent sides establishing open communicationbetween the inlet passage and the forward portion of the bore, and aplurality of circumferentially spaced orifices establishing opencommunication between the rear portion of the bore and the outletpassage and adapted to establish a pressure drop between the inllowingand outllowing fluid, an elongate plunger in the bore and having apiston head at one end to normally occur forward of the metering portsand establishing sliding sealing engagement in the bore, a base at theother eind of the plunger to occur rearward of the orifices andestablishing sliding sealing engagement in the bore, a longitudinal flowpassage entering the forward end of the plunger and a lateral port inthe plunger rearward of the piston and communicating with the flowpassage to conduct fluid into the bore forward of the piston to shiftthe piston rearwardly to overlie the metering ports and control the owof fluid therethrough, buffer means conducting fluid into and out of thebore rearward of the base to control the rate of movement of theplunger, and spring means in the bore to act on the base of the plungerand normally yieldingly urging the plunger and the piston forward in thebore.

6. A flow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage in the front end of thebody, an outlet passage in the rear end of the body, an elongatelongitudinally disposed bore in the body extending between and connectedwith the inlet and outletpassages, an elongate flow control sleeve ofsmaller diameter than the bore in the body and engaged in the bore inthe body to extend between the inlet and outlet passages, a flangepartition intermediate the ends of the sleeve and sealed with the borein the body toestablish upstream and downstreai'n` asoma@ 7 chambersabout the sleeve,A a central longitudinally dis.-V posed cylinder borevin the sleeve, heads at the ends of the sleeve and closing the. cylinderbore, a metering`r port in4 thesleeve forward of the ange; andestablishing open communication between the upstream Chamber and thecylinder bore, an orifice inl the. sleeve rearward of the flange and.establishing open communication between the cylinder bore and thedownstream chamber and adapted to establish a pressure drop between thefluid in tho4 @YU-l1.-y der` bore and the fluid in the downstreamchamber, an elongate plunger in the cylinder bore having a base spacedrearward of the orifice, a stem` of reduced diameter projectingforwardly from the base,A and a piston` head at the forward end of thestem to normally occur forward of, the metering port, a longitudinalflow passage extend-A ing. into the plunger from the front end of thepiston, a lateral port in the stem and communicating with the flowpassage, said late-ral port and flow passage adapted to conduct lluidinto the cylinder bore forward of the piston to urge the pistonrearwardly intolapped engagement with the metering. Port in the sleeveto control the ow of llu'id therethrough, an orifice in the head at therear end of the sleeve and conducting fluid into and ont of the cylinderbore rearward of the plunger base, and a compression spring in thecylinder bore betweenthe plunger base and the head at the rear end ofthe sleeve, and normally yieldingly urging the plunger forward andagainst the action of Huid on the piston head.

7. A flow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage in the front end of thebody, an outlet passage in the rear end of the body, an elongatelongitudinally disposed bore in the body extending between and connectedwith the inlet and outlet passages, an elongate ow con-v trol sleeve ofsmaller diameter than the bore in the body and engaged in the bore inthe body to extend between the inlet and outlet passages, a radiallyoutwardly proa jecting flange-like partition intermediate the ends ofthe sleeve and sealed with the bore in the body to establish upstreamand downstream chambers about the sleeve, Aa central longitudinallydisposed cylinder bore in the sleeve, heads at the ends of the sleeveand closing the cylinder bore, a plurality of circumferentially spacedmetering ports in the sleeve forward of the iiange and establishing opencommunication between the upstream chamber and the cylinder bore, aplurality of circumferentially spaced oriices in the sleeve rearward ofthe flange and establishing-open communication between the cylinderborerand the downstream chamber and adapted to establish a pressure dropbetween the uid in the cylinder bore and the fluid in the downstreamchamber, an elongate plunger in `the cylinder bore having a base spacedrearward of the orices, a stem of reduced diameter projecting forwardlyfrom the base, and a piston head at the forward end of the stem tonormally occur forward of the meter ing ports, a longitudinal flowpassage extending into the plunger from the front end of the piston anda lateral port inthe stem and communicating with the flow passage, saidlateral port and ow passage adapted to conduct uid into the cylinderbore forward of the piston to urge the piston rearwardly into lappedengagement with the metering port in the sleeve to control the low ofuid therethrough, an orifice in the head at the rear end of the sleeveand conducting iluid into and out of the cylinder bore rearward of theplunger base, and a compression spring in the cylinder bore between theplunger base and the head at the rear end of the sleeve land normallyyieldingly urging the plunger forward and against the action of the uidon vthe piston head.

8. A ow limiter of the character described including, an elongate bodyhaving front and rear ends, an inlet passage 'in the front end of ythebody, an outlet passage in the rear lend of the body, lan elongatelongitudinally disposed bore in the body `extending between andconnested with the -inletrand outlet passages, Aan elongate How controlsleeve ofy smaller; diameter than the bore in the body and engaged intha bo o. in the body to a tend bef tween; the inlet; and outletpassages; a dansoflilse n tition intermediate the ends ot tbe Sleeve andsea-led with the bore in the body to establish upstream and down:Istream chambers about the sleeve, a oantral longitudinallydisposodcylinder boro, in the, sleeve, heads at the ends of the sleeve andclosing the cylinder bore, a semi-.curve linear triangular motoringport. having a base extending transverse the longitudinal aXisof tbesleeve and rearwardly convergent Convex sides in the sloot/o forward otthey Hansa and establishing open oornnlunication between. the upstreamchamber and .tba Cylinder bore., an oridao in the sleeve .rearward otthe. flange, and. establishing onen communication between the cylinderboro and tbe downrstroam chamber .and adapted. to establish a pressuredrop between tbe fluid inv tho cylinder; boro and tho duid tbadownstream chamber, .an elongate plunger in tha cylinder; bora having abase spaced. rearward of the oriioe, a stent of reduced diameterprojecting forwardly troni the base. and a. piston bead at the forwardond of the stom to normally occur forward of tho motoring ports, alonsifv tudinal llow passage extending into the plunger from the frontend. ot the. piston and a. lateral Port in the Stern.

l and communicating with. tho dow passage, said lateral port and flowpassage adapted. to conduct duid into tho Cylinder boro forward ot thepiston to Urso tho Piston rearwardly into lapped engagement with themetering port in the sleeve to 4control the flow of fluid therethrough,an orica in .tho head at tha roar and of tho sleeve.. and conductingfluid into and ont of the oylindor bora roar-` ward ofthe plunger base,and a compression spring in the .cylinder boro between, the plunger basaand the bead at the rear end of the sleeve and normally yieldinglyurgingthe plunger forward and against the action of tho duid on thepiston head.

9. A ilow limiter of the character described including, an elongate bodyhaving yfront and rear ends, an `inlet passage in the front end of thebody, an outlet passage in the rear end of the body, an elongatelongitudinally disposed bore in the. body extending botwoon andConnected with the inlet and ,olllot passages, an elongate How controlsleeve of smaller diameter than the bore in the body and engaged in thebore in the body to extend between` the inlet and outlet passages, aradially outwardly pro.- jecting ange-like partition intermediate theends of the sleeve and sealed with lthe bore lin the body to establishupstream and downstream chambers about the sleeve, a centrallongitudinally disposed cylinder bore in the sleeve, heads at the ends`of the sleeve and closing the cylinder bore, a plurality lofcircumferentially spaced semi-.curvi-A linear triangular metering portshaving rearwardly con,- vergentsides in the sleeve forward of the flangeand establishing open communication between the upstream cham-l ber andthe cylinder bore, an oriiice in the sleeve rearward of the flange andVestablishing open communication between the cylinder bore and thedownstream chamber and adapted to establish apressure drop between theiluid in the cylinder bore and the iluid in the downstream chamber, anelongate plunger in ,the cylinder bore having a base spaced rearward ofthe orifice, a stern .of reduced diameter projecting forwardly from thebase, and a piston head at the forward end of the stem to normally occurforward of themetering ports, a longitudinal ow passage extending intothe plunger from the front end of the piston and a lateral port in thestem and communicating with the ow passage, said lateral port and flowpassage adapted to conduct uid into the cylinder bore forward of thepiston to urge the piston lrearwardly into lapped engagement with themetering port in the sleeve to control the iiow of fluid therethrough,buler means to control the `rate at which the plunger moves in thesleeve and in- Clildins anorifloe in the headat. tho rear .and of the.sloovo and conducting tluid into and out, of the .cylindorboro rearward`of theplunger base, and a compression spring in the cylinder borebetween the plunger base and the head at the rear end of the sleeve andnormally yieldingly urging the plunger forward and against the action ofthe uid on the piston head.

10. A flow limiter of the character described, including, an elongatebody having front and rear ends, an inlet passage in the front end ofthe body, an outlet passage in the rear end of the body, an elongatelongitudinally disposed bore in the body extending between and connectedwith the inlet and outlet passages, an elongate flow control sleeve ofsmaller diameter than the bore in the body and engaged in the bore inthe body to extend between the inlet and outlet passages, a radiallyoutwardly projecting flange-like partition intermediate the ends of thesleeve and sealed with the bore in the body to establish upstream anddownstream chambers about the sleeve, a central longitudinally disposedcylinder bore in the sleeve, heads at the ends of the sleeve and closingthe cylinder bore, a plurality of circumferentially spacedsemi-curvilinear triangular metering ports in the sleeve forward of theange having bases extending transverse the longitudinal axis of thesleeve and having rearwardly convergent sides and establishing opencommunication between the upstream chamber and the cylinder bore, aplurality of circumferentially spaced orifices in the sleeve rearward ofthe flange and establishing open communication between the cylinder boreand the downstream chamber and adapted to establish a pressure dropbetween the fluid in the cylinder bore and the lluid in the downstreamchamber, an elongate plunger in the cylinder bore having a base spacedrearward of the on'ces, a stem of reduced diameter projecting forwardlyfrom the base, and a piston head at the forward end of the stem tonormally occur forward of the metering ports, a longitudinal flowpassage extending into the plunger from the front end of the piston anda lateral port in the stem and communicating with the ow passage, saidlateral port and flow passage adapted to conduct uid into the cylinderbore forward of the piston to urge the piston rearwardly into lappedengagement with the metering port in the sleeve to control the ow of uidtherethrough, buffer means to control the rate at which the plungermoves in the sleeve and including an orifice in the head at the rear endof the sleeve and conducting uid into and out of the cylinder borerearward of the plunger base, and a compression spring in the cylinderbore between the plunger base and the head at the rear end of the sleeveand normally yieldingly urging the plunger forward and against theaction of the iluid on the piston head.

References Cited in the le of this patent UNITED STATES PATENTS2,570,317 Busson Oct. 9, 1951 2,646,078 Adams July 21, 1953

